Gas Injection Optimization in a Giant Offshore Carbonate Field and Impact on Field Development Plan. Case Study

Abstract

Gas injection is a part of secondary recovery factor to improve reservoir sweep efficiency and recovery factor. However defining optimum gas injection rate in a multi layered heterogeneous carbonate reservoirs is a big challenge and any deviation from optimum gas injection rate can cause fast Gas Cap expansion or fast reservoir depletion. Proper dynamic synthesis of the multi layered reservoir was performed. Openhole logs and available cased hole logs were QCed and reinterpreted for better undestanding of fluid movement. Efficient gas injection rate for each string and balance between water injection and gas injection were evaluated. Gas tracers study was carried out by injecting gas tracers into gas injection wells. The results of the study were used for optimizing the gas injection strategy. As a result of overall gas injection optimization, a positive impact is observed on the total field gas production rate or total field GOR which has been reduced and many oil wells became active resulted in additional oil production gain.